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At large N_c the nucleon can be viewed as a soliton of the effective chiral lagrangian. This picture of nucleons allows a consistent nonperturbative calculation of the leading-twist parton distributions at a low normalization point. We…

High Energy Physics - Phenomenology · Physics 2009-10-28 D. Diakonov , V. Petrov , P. Pobylitsa , M. Polyakov , C. Weiss

In the large momentum transfer limit, generalized parton distributions can be calculated through a QCD factorization theorem which involves perturbatively-calculable hard kernels and light-cone parton distribution amplitudes of hadrons. We…

High Energy Physics - Phenomenology · Physics 2009-11-10 Pervez Hoodbhoy , Xiangdong Ji , Feng Yuan

Interactions of virtual photons are analyzed in terms of photon structure. It is argued that the concept of parton distribution functions is phenomenologically very useful even for highly virtual photons involved in hard collisions. This…

High Energy Physics - Phenomenology · Physics 2009-10-31 Jiri Chyla , Marek Tasevsky

We study parametrization of polarized parton distribution functions in the \alpha_s leading order (LO) and in the next-to-leading order (NLO). From \chi^2 fitting to the experimental data on A_1, optimum polarized distribution functions are…

High Energy Physics - Phenomenology · Physics 2009-10-31 M. Hirai , H. Kobayashi , M. Miyama

We present a first calculation of the generalized parton distributions of the photon(both polarized and unpolarized) using overlaps of light-front wave functions at leading order in \alpha and zeroth order in \alpha_s; for non-zero…

High Energy Physics - Phenomenology · Physics 2015-05-28 A. Mukherjee , S. Nair

Factorization scheme analysis of $F_2^{\gamma}(x,Q^2)$ in the next-to-leading order QCD is revisited. It is emphasized that the presence of the inhomogeneous term in the evolution equations for quark distribution functions of the photon…

High Energy Physics - Phenomenology · Physics 2007-05-23 Jiri Chyla

The freedom associated with the definition of parton distribution functions is analyzed and formulae governing the dependence of parton distribution functions and hard scattering cross-sections on unphysical quantities associated with the…

High Energy Physics - Phenomenology · Physics 2011-12-20 Karel Kolar

We review the current status of Parton Distribution Function (PDF) determinations for unpolarized and longitudinally polarized protons and for unpolarized nuclei, which are probed by high-energy hadronic scattering in perturbative Quantum…

High Energy Physics - Phenomenology · Physics 2020-02-18 Jacob J. Ethier , Emanuele R. Nocera

The electron, positron, and photon Parton Distribution Functions (PDFs) of the unpolarised electron have recently been computed at the next-to-leading logarithmic accuracy in QED, by adopting the $\overline{\rm MS}$ factorisation scheme. We…

High Energy Physics - Phenomenology · Physics 2021-12-22 Stefano Frixione

It has been suggested that parton distributions in coordinate space, so called Ioffe-time distributions, provide a more natural object for non-perturbative methods compared to the usual momentum distributions. In this paper we argue that…

High Energy Physics - Phenomenology · Physics 2009-10-28 L. Mankiewicz , T. Weigl

Using QCD motivated and phenomenological considerations, we construct x- dependent polarized parton distributions, which evolve under GLAP evolution, satisfy DIS data and are within positivity constraints. Each flavor is done separately and…

High Energy Physics - Phenomenology · Physics 2014-11-17 Lionel E. Gordon , Mehrdad Goshtasbpour , Gordon P. Ramsey

Sets of parton distribution functions (PDFs) of the proton are reported for the leading (LO), next-to-leading (NLO) and next-to-next-to leading order (NNLO) QCD calculations. The parton distribution functions are determined with the…

We analyze the moments of parton distribution functions in the pion calculated in lattice QCD, paying particular attention to their chiral extrapolation. Using the lowest three non-trivial moments calculated on the lattice, we assess the…

High Energy Physics - Lattice · Physics 2008-11-26 W. Detmold , W. Melnitchouk , A. W. Thomas

We report on a calculation of the generalized parton distributions of the photon when there is non-zero momentum transfer both in the transverse and longitudinal directions. By taking Fourier transforms of the GPDs with respect transverse…

High Energy Physics - Phenomenology · Physics 2015-06-30 Asmita Mukherjee , Sreeraj Nair

We study deeply virtual Compton scattering on a virtual pion that is emitted by a proton. Using a range of models for the generalized parton distributions of the pion, we evaluate the cross section, as well as the beam spin and beam charge…

High Energy Physics - Phenomenology · Physics 2008-12-18 Daniela Amrath , Markus Diehl , Jean-Philippe Lansberg

We present new NLO sets of parton distributions in real photons based on a scheme invariant definition of the non-perturbative input. We compare the theoretical predictions with LEP data and a best fit allows us to constrain the parameters…

High Energy Physics - Phenomenology · Physics 2009-01-07 P. Aurenche , M. Fontannaz , J. Ph. Guillet

We consider distributions of unpolarized (polarized) quarks in unpolarized (polarized) hadrons. Our approach is based on QCD factorization. We begin with study of Basic factorization for the parton-hadron scattering amplitudes in the…

High Energy Physics - Phenomenology · Physics 2015-06-01 B. I. Ermolaev , M. Greco , S. I. Troyan

We present a consistent calculation of the structure functions within a light-front constituent quark model of the nucleon. Relativistic effects and the relevance of the covariance constraints are analyzed for both polarized and unpolarized…

High Energy Physics - Phenomenology · Physics 2009-10-31 P. Faccioli , M. Traini , V. Vento

We present a study of the results obtained combining LO partonic matrix elements with different orders of partons distributions. These are compared to the best prediction using NLO for both matrix elements and parton distributions. The aim…

High Energy Physics - Phenomenology · Physics 2007-06-15 R. S. Thorne , A. Sherstnev , C. Gwenlan

Optimum nuclear parton distributions are determined by an analysis of muon and electron deep inelastic scattering data. Assuming simple A dependence and polynomial functions of x and 1-x for nuclear modification of parton distributions, we…

High Energy Physics - Phenomenology · Physics 2015-06-25 M. Hirai , S. Kumano , M. Miyama